Question

Please I would like to know what are the Eflluents and waste materials generated in large scale bio Ethanol plants making Ethanol form sugar beet.

Thanks

Answer 1

Ans) Waste materials generated in production of ethanol from sugar beet are as follows :

1) In Reactive distillation of sugar beets to form ethanol a compound is added to the mixture which reacts reversibly with one of the component of the mixture giving a product which has different boiling point and is needed to be seperated out from the mixture.After its removal, distillation is further carried out  

2) During sucrose extraction, Cossets (cutted smaller pieces of sugar beets) are pressed to obtain raw juice.The pressed pulp

is a waste and generally dumped in landfills or feeded to cattles  

3) Calcium carbonate - During Filtration process of sucrose, impurities in the sucrose are removed by treating it with lime.Carbon dioxide is also passed through the mixture which results in formation of calcium carbonate which precipitate at the base of the tank along with large number of impurities in the mixture.This calcium is the waste material formed and is separated out from the mixture. Along with calcium carbonate, effluents such as some water and remaining calcium hydroxide are also removed to obtain pure sucrose mixture

4) Glycerol - During fermentation of sucrose with S.Cerevisiae (an species of yeast) around 1% weight by volume of sucrose is formed as waste product and seperated out

5) Yeast cells - During final stage after the fermentation of sucrose , yeast cells remaining in the ethanol are also seperated out as effluents